This invention relates to a method and apparatus for testing for the presence of microorganisms.
At the present time, it is necessary to perform sterility tests on samples of pharmacological compositions and apparatus to comply with federal regulations in the United States and similar regulations in other nations.
Any such testing procedure must prevent adventitious microbial growth transmitted to the article or composition being tested or to the substrate containing a test culture medium from the environment; otherwise, the test results are invalid. Therefore, it is necessary to demonstrate that the proper precautions have been taken to exclude extraneous microorganisms throughout the test period.
When testing sterilized dry solids, the dry solid or a suspension or solution of the dry solid is transferred from its container, e.g. ampoule, to a sterile chamber where it is mixed with a growth medium. Prior to the present invention, it was common practice to pour by hand the contents of the ampoule into the sterile chamber, thereby increasing the chances of contamination. The suspension or solution in the sterile chamber then is contacted with a growth medium and incubated. Typically, for bacteria, a thioglycollate medium has been utilized which includes a resayurin additive to provide for color indication, and also agar to inhibit diffusion throughout the medium. A medium which is particularly useful for determining the presence of fungi is soybean-casein digest medium. Another medium which is utilized for this latter purpose is a Sabouraud medium. The presently utilized technique for testing powders requires two week incubation time and increases the risk of hand contamination, thereby causing an excessive number of false positive tests. Obviously, false positive tests are undesirable, for example, since they require resterilization of the entire batch or product which increases the risk of ruining the batch or product.
It would be highly desirable to provide a procedure for testing the powdered contents of an ampoule which eliminates or minimizes the risk of hand contamination during the test procedure.